1. Field of the Invention
The present invention relates to a nail gun in general, and more particularly, to a nail gun attachment in the form of a spacer which prevents compressing and crushing a building material when installed over a structure using nails.
2. Reported Developments
Nail guns are well-known in the prior art and their use in building construction greatly improves the speed, safety and accuracy of attaching together construction elements by the use of nails. Examples of nail guns can be found in U.S. Pat. Nos. 5,261,588, 5,180,091 and 4,570,840.
Briefly described, a nail gun comprises:                a driving cylinder for ejecting nails upon actuation thereof;        a handle of a generally rectangular, closed loop configuration coupled to a peripheral side wall; and        a trigger mounted on an intersection between the driving cylinder and the handle for selectively actuating the driving cylinder.        
Nail guns provide for easy, convenient and fast delivery of nails into building materials for fastening such materials to each other. Certain building materials, however, require attachment to nail guns for affixing layers of sheet materials together without damaging the materials intended for special uses, as exemplified by the following.
In the building industry when two sheets of materials are being fastened together it is necessary to space the two sheets of materials at a pre-determined distance apart from each other, such as when installing dry walls, placing foam insulation between vinyl or aluminum siding panels and outer wall sheathing, or installing a roof ridge vent using a synthetic fiber matting covered by asphalt cap shingles. The nails used, without a provision for spacing the sheet materials apart from each other, tend to crush the soft materials or cause indentations around the nails in the composite materials. Such indentation vary from minor indentation resulting in less than aesthetically pleasing appearance to the reduction in insulating efficacy of the composite material. An example of the latter occurrence is the installation of a mat made of randomly aligned synthetic fibers joined by phenolic or latex bonding which is heat cured to provide the mat with varying mesh. This material is sold by GAF Materials Corporation, and is available under the name COBRA(c) Ridge Vent and is described in U.S. Pat. No. 5,167,579. When the COBRA(c) mat is nailed to the ridge vent, then covered by shingles using manual installation techniques, or nail guns without having a means to keep the two layers spaced from each other the mat is compressed by being crushed by the nails resulting in loss of the R value of the mat.
U.S. Pat. No. 5,511,918 discloses a nail used manually or with a pneumatic gun for securing two materials together spaced by an interposed resilient material. The nail has a head at one end, a shaft extending from the head and terminating in a sharp point. The nail is equipped with a sleeve having a cylindrical center portion and a pair of frusto-concical tapered portion. The sleeve surrounds the shaft and has a length in excess of the resilient material and less than the length of the shaft.
The method of using the nail equipped with the sleeve to affix two sheets together interposed by a resilient layer includes the steps of:                laying the first sheet on a supportive substrate;        laying the resilient layer on top of the first sheet;        laying the second sheet on top of the resilient material;        driving the point of the nail through the second sheet, the resilient layer and into the first sheet.        
The cutting edge of the sleeve cuts the second sheet and the resilient layer. The cutting edge of the sleeve stops at the first sheet without penetrating the first sheet for the reason that the length of the sleeve is no more than the combined thickness of the first sheet and the resilient layer. As a result of the limiting length of the sleeve the resilient layer is not crushed or compressed by the nail. However, it will be noted by those skilled in the art that while this invention greatly reduces the compression of the resilient layer in the vertical direction, the sleeve exerts a compression or crushing force in the lateral direction. The extent of such compressive or crushing forces is proportional to the thickness of the sleeve. An object of the present invention is to reduce such compressive or crushing forces both in the vertical and the lateral directions.
U.S. Pat. No. 5,564,614 is directed to a nailing depth adjusting mechanism for a pneumatic nail gun comprising: a firing control strip fastened to the gun and driven to release the firing pin thereof; and a wheel for adjusting the nailing depth of the gun.
The present invention utilizes a concept which is different from those of the prior art in providing an attachment to a nail gun by which compression and/or crushing a fibrous material interposed between two sheets is prevented.